Physicians aren’t great at differentiating bacterial versus viral conjunctivitis. Especially in kids this leads to the provision of antibiotics regardless of etiology. This post will discuss antibiotics agents and therapeutic considerations – including return to school/daycare. Whether you are a network anchor or 4 year old preschooler conjunctivitis will lead to some pretty disruptive symptoms. Neonatal conjunctivitis is another issue altogether and won’t be covered here. I approach conjunctivitis by first considering what features should prompt evaluation by an Ophthalmologist as they are harbingers of more significant issues:
- Decreased visual acuity
- History of trauma and/or foreign body sensation
- Opaque cornea
- Fixed or asymmetric pupils
- Severe headache with nausea
The bottom line is that viral and allergic conjunctivitis are self limited illnesses. Though treatment may reduce symptoms there is no benefit on reducing the length of the illness & symptoms. This was demonstrated in a RCT by Rose et al that saw no difference between placebo and chloramphenicol. They noted that “clinical cure by day 7 occurred in 128 (83%) of 155 children with placebo compared with 140 (86%) of 162 with chloramphenicol (risk difference 3.8%, 95% CI -4.1% to 11.8%).” This study also included performance of culture swabs for virus and bacterial etiologies – and though those aren’t the most sensitive assays – still allowed to authors to draw some conclusions about the probable self-limited nature of bacterial conjunctivitis as well. A Cochrane review from Sheikh at al. noted the following:
- Topical antibiotics benefitted ‘early’ (days 2-5) clinical (RR = 1.36, 95% CI = 1.15 to 1.61) and microbiological (RR = 1.55, 95% CI = 1.37 to 1.76) remission rates
- Treatment at later stages (days 6-10) still resulted in some benefits in clinical remission (RR = 1.21, 95% CI = 1.10 to 1.33) and microbiological cure rates (RR = 1.37, 95% CI = 1.24 to 1.52)
- By day 10, 41% (95% CI = 38 to 43) of cases had resolved in those receiving placebo
In summary, this systematic review presented data that showed that if you are going to treat, you were more likely to confer benefit in clinical symptom remission and microbiologic cure if you start topical antibiotics before day 6.
Recommended antibiotic choices
There are two great first choices:
- Erythromycin ophthalmic ointment: 1/2 inch = 1.25cm ointment deposited into the lower lid 4 times daily for 5-7 days
- Polymyxin/trimethoprim drops: 1-2 drops instilled 4 times daily for 5-7 days
Patients should expect to see a response in 1-2 days with decreased redness, discharge and irritation. Ointment may be better for many children because – moving target. Obviously ointment can blur vision for 10-20 minutes so students and adolescents (especially drivers) should get drops.
Other therapeutic options
- Sulfacetamide ointment & Sulfa drops are no longer widely prescribed due to concerns about the risk of allergic reactions
- Bacitracin ointment
- Fluoroquinolone drops: The treatment for corneal ulcers (pseudomonas) and conjunctivitis in contact lens wearers
- Azithromycin drops: Dosed less often – 1 drop twice daily for 2 days, then one drop daily for 5 days, but a lot more expensive
- Aminoglycosides (gentamicin) are toxic to the corneal epithelium causing a reactive keratoconjunctivitis over a few days use
- Antibiotics for viral conjunctivitis – OTC lubricating agents will do the job if that has been your rationale for prescribing antibiotics.
- Glucocorticoids: They can cause melting of the cornea if used in herpes or fungal eye infections and certain forms of viral keratitis. This includes combination steroid/antibiotic drops. Leave the ‘roods to the professionals (eye doctors).
- Antibiotics empirically without examining the patient. This issue often arises when parents call the on call physician and request drops because their child can’t go back to school or day care without them. Most daycare centers and schools require that students with conjunctivitis receive 24 hours of topical therapy before returning to school. If you insist upon prescribing sight unseen (or if a sibling has a confirmed case) use erythro ointment or Polytrim.